Tay Bridge: Difference between revisions
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[[Image:Tay2.jpg]] |
[[Image:Tay2.jpg|thumb|300px|Second Tay Bridge, Central section.]] |
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[[Image:Taybr01.jpg|thumb|300px|Original Tay Bridge from the north]] |
[[Image:Taybr01.jpg|thumb|300px|Original Tay Bridge from the north]] |
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[[Image:Tay bridge down.JPG|thumb|300px|Fallen Tay brdge from the north]] |
[[Image:Tay bridge down.JPG|thumb|300px|Fallen Tay brdge from the north]] |
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Investigators quickly determined that the cylindrical [[cast iron]] columns supporting the 13 longest [[span (architecture)|spans]] of the bridge, each 245 ft (75 m) long, were of poor quality. In particular, the [[lug]]s used to attach the [[wrought iron]] bracing bars were moulded with the columns, introducing a fatal weakness. It was these lugs that failed first in the accident, and so destabilised the entire centre part of the bridge. No allowance for wind load had been made by Bouch; such calculations were not common practice until precipitated by the disaster. The High Girders section in the middle of the bridge was top heavy, making this part insecure. It was this section that collapsed. |
Investigators quickly determined that the cylindrical [[cast iron]] columns supporting the 13 longest [[span (architecture)|spans]] of the bridge, each 245 ft (75 m) long, were of poor quality. In particular, the [[lug]]s used to attach the [[wrought iron]] bracing bars were moulded with the columns, introducing a fatal weakness. It was these lugs that failed first in the accident, and so destabilised the entire centre part of the bridge. No allowance for wind load had been made by Bouch; such calculations were not common practice until precipitated by the disaster. The High Girders section in the middle of the bridge was top heavy, making this part insecure. It was this section that collapsed. |
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It has been speculated that the bridge may have been fatally weakened by [[waterspout|waterspouts]] that had been seen in the vicinity immediately prior to the disaster. [http://www.torro.org.uk/TORRO/research/whirlextreme.php] |
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====Official inquiry==== |
====Official inquiry==== |
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Revision as of 10:36, 5 February 2007
The Tay Bridge (sometimes unofficially the Tay Rail Bridge) is a railway bridge approximately two and a quarter miles (three and a half kilometres) long[1] that spans the Firth of Tay in Scotland, between the city of Dundee and the suburb of Wormit in Fife (grid reference NO391277).
As with the Forth Bridge, the Tay Bridge has also been called the Tay Rail Bridge since the construction of a road bridge over the firth, the Tay Road Bridge. The rail bridge replaced an early train ferry.
The first Tay Bridge
The original Tay Bridge was constructed in the 19th century by noted railway engineer Thomas Bouch, who received a knighthood following the bridge's completion. It was a lattice-grid design, combining cast and wrought iron. The design was well known, having been used first by Kennard in the Crumlin viaduct in South Wales in 1858, following the innovative use of cast iron in The Crystal Palace. However, this structure was not as heavily loaded as a railway bridge, such as the Dee bridge, which collapsed in 1847 due to poor use of cast-iron girders. Later, Gustave Eiffel used a similar design to create several large viaducts in the Massif Central (1867).
Proposals for constructing a bridge across the River Tay date back to at least 1854. The North British Railway (Tay Bridge) Act received the Royal Assent on July 15 1870 and the foundation stone was laid on July 22 1871. The first engine crossed the bridge on September 22 1877, and upon its completion in early 1878 the Tay Bridge was among the longest in the world. The bridge was officially opened by Queen Victoria on June 1 1878.
While visiting the city, Ulysses S. Grant commented that it was "a big bridge for a small city".
The Tay Bridge Disaster
During a violent storm on the evening of 28 December 1879, the centre section of the bridge, known as the "High Girders", collapsed, taking with it a train that was running on its single track. More than 75 lives were lost, including Sir Thomas' son-in-law. (A common urban myth in Dundee is that Karl Marx would have been a passenger on the train had illness not prevented him from travelling.)
Investigators quickly determined that the cylindrical cast iron columns supporting the 13 longest spans of the bridge, each 245 ft (75 m) long, were of poor quality. In particular, the lugs used to attach the wrought iron bracing bars were moulded with the columns, introducing a fatal weakness. It was these lugs that failed first in the accident, and so destabilised the entire centre part of the bridge. No allowance for wind load had been made by Bouch; such calculations were not common practice until precipitated by the disaster. The High Girders section in the middle of the bridge was top heavy, making this part insecure. It was this section that collapsed.
Official inquiry
The official inquiry was chaired by Henry Cadogan Rothery, Commissioner of Wrecks, supported by Colonel Yolland (Inspector of Railways) and civil engineer William Henry Barlow. They concluded that the bridge was "badly designed, badly built and badly maintained, and that its downfall was due to inherent defects in the structure, which must sooner or later have brought it down".
There was clear evidence that the central structure had been deteriorating for many months before the final accident. The maintenance inspector, Henry Noble, had heard the joints of the wrought-iron tie-bars "chattering" a few months after the bridge opened in June 1878, a sound indicating that the joints had loosened. This made many of the tie-bars useless for bracing the cast-iron piers. Noble did not attempt to re-tighten the joints, but hammered shims of iron between them in an attempt to stop the rattling.[2]
The problem continued up till the collapse of the High Girders. It indicated that the centre section was unstable to lateral movement, movement that had been observed by painters working on the bridge in the summer of 1879. Passengers on north-bound trains complained about the strange motion of the carriages, but they were ignored by the bridge's owners, the North British Railway. Some distinguished passengers, such as the Provost of Dundee, had timed trains moving across the bridge and found they were travelling at about 40 mph, well in excess of the official limit of 25 mph.
The enquiry demolished Bouch's professional reputation: "For these defects both in the design, the construction and the maintenance, Sir Thomas Bouch is, in our opinion, mainly to blame. For the faults of design he is entirely responsible". The Board of Trade, concerned about Bouch's design for the planned Forth Bridge on the same railway line, imposed a specification of 56 pounds force per square foot (2.7 kPa). The contract for the new Forth Bridge was awarded to William Arrol using designs by Benjamin Baker and John Fowler. Bouch died within a year of the disaster.
Only the locomotive (NBR 224) survived the disaster, being salvaged from the river and repaired at Cowlairs. It remained in service until 1919.
Verses inspired by the disaster
The Victorian poet William Topaz McGonagall commemorated this event in his famous (perhaps infamous) poem The Tay Bridge Disaster. Likewise, German poet Theodor Fontane, shocked by the news, wrote his poem Die Brück' am Tay (with obvious allusions to William Shakespeare and Friedrich von Schiller). It was published only ten days after the tragedy had happened.
A second bridge
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A new double-track bridge was designed by William Henry Barlow and built by William Arrol 60 ft (18 m) upstream of, and parallel to, the original bridge. The bridge proposal was formally incorporated in July 1881 and the foundation stone laid on July 6 1883. Construction involved 25,000 tons of iron and steel, 70,000 tons of concrete, ten million bricks (weighing 37,500 tons) and three million rivets. Fourteen men lost their lives during its construction, mostly due to drowning.
The second bridge opened on 13 July 1887 and remains in use. In 2003, a £20.85 million strengthening and refurbishment project on the bridge won the British Construction Industry Civil Engineering Award, in consideration of the staggering scale and logistics involved. More than 1,000 tonnes of bird droppings were scraped off the ironwork lattice of the bridge using hand tools, and bagged into 25 kg sacks. Hundreds of thousands of rivets were removed and replaced. All this work was done in very exposed conditions, high over a firth with fast-running tides.
The stumps of the original bridge piers are still visible above the surface of the Tay at low tide.
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Trivia
"Tay Bridge" was the codename for the funeral plans for Queen Elizabeth, The Queen Mother.
References
Notes
- ^ including a brick viaduct.
- ^ Rolt, L T C (1955): Red for danger. The Bodley Head, London.
Bibliography
- Charles Matthew Norrie, Bridging the Years: A Short History of British Civil Engineering, Edward Arnold (Publishers) Ltd., 1956.
- John Thomas, The Tay Bridge Disaster: New Light on the 1879 Tragedy, David & Charles, 1972, ISBN 0-7153-5198-2.
- John Prebble, The High Girders: The Story of the Tay Bridge Disaster, Penguin Books, 1975, ISBN 0-14-004590-2.
- David Swinfen, The Fall of the Tay Bridge, Mercat Press, 1998, ISBN 1-873644-34-5.
- Peter R. Lewis, Beautiful Railway Bridge of the Silvery Tay: Reinvestigating the Tay Bridge Disaster of 1879, Tempus, 2004, ISBN 0-7524-3160-9.
- Charles McKean Battle for the North: The Tay and Forth bridges and the 19th century railway wars Granta, 2006, ISBN 1-86207-852-1
External links
- Tom Martin's engineering analysis of the bridge disaster
- Tay Bridge page on railscot.co.uk
- Old Photographs: Trains
- BBC website devoted to the Tay bridge disaster
- Paper on the disaster
- Recent review of book on the disaster — go to Failure Magazine; select "Archives" & then search for Tay Bridge.
- Template:PDFlink Tay Bridge Disaster: Report Of The Court of Inquiry, and Report Of Mr. Rothery, Upon the Circumstances Attending the Fall of a Portion of the Tay Bridge on the 28th December 1879 from The Railways Archive.